token_bucket/tests/test_token_bucket.nim
2025-07-17 15:12:06 +03:00

252 lines
9.8 KiB
Nim

# Chronos Test Suite
# (c) Copyright 2022-Present
# Status Research & Development GmbH
#
# Licensed under either of
# Apache License, version 2.0, (LICENSE-APACHEv2)
# MIT license (LICENSE-MIT)
{.used.}
import testutils/unittests
import chronos
import ../src/token_bucket
suite "Token Bucket":
test "TokenBucket Sync test - strict":
var bucket = TokenBucket.newStrict(1000, 1.milliseconds)
let
start = Moment.now()
fullTime = start + 1.milliseconds
check:
bucket.tryConsume(800, start) == true
bucket.tryConsume(200, start) == true
# Out of budget
bucket.tryConsume(100, start) == false
bucket.tryConsume(800, fullTime) == true
bucket.tryConsume(200, fullTime) == true
# Out of budget
bucket.tryConsume(100, fullTime) == false
test "TokenBucket Sync test - compensating":
var bucket = TokenBucket.new(1000, 1.milliseconds)
let
start = Moment.now()
fullTime = start + 1.milliseconds
check:
bucket.tryConsume(800, start) == true
bucket.tryConsume(200, start) == true
# Out of budget
bucket.tryConsume(100, start) == false
bucket.tryConsume(800, fullTime) == true
bucket.tryConsume(200, fullTime) == true
# Due not using the bucket for a full period the compensation will satisfy this request
bucket.tryConsume(100, fullTime) == true
test "TokenBucket Max compensation":
var bucket = TokenBucket.new(1000, 1.minutes)
var reqTime = Moment.now()
check bucket.tryConsume(1000, reqTime)
check bucket.tryConsume(1, reqTime) == false
reqTime += 1.minutes
check bucket.tryConsume(500, reqTime) == true
reqTime += 1.minutes
check bucket.tryConsume(1000, reqTime) == true
reqTime += 10.seconds
# max compensation is 25% so try to consume 250 more
check bucket.tryConsume(250, reqTime) == true
reqTime += 49.seconds
# out of budget within the same period
check bucket.tryConsume(1, reqTime) == false
test "TokenBucket Short replenish":
var bucket = TokenBucket.new(15000, 1.milliseconds)
let start = Moment.now()
check bucket.tryConsume(15000, start)
check bucket.tryConsume(1, start) == false
check bucket.tryConsume(15000, start + 1.milliseconds) == true
test "TokenBucket getAvailableCapacity strict":
let now = Moment.now()
var reqTime = now
var bucket =
TokenBucket.new(1000, 1.minutes, ReplenishMode.Strict, lastTimeFull = now)
# Test full bucket capacity ratio
let lastTimeFull_1 = reqTime
check bucket.getAvailableCapacity(reqTime) == (1000, 1000, lastTimeFull_1)
# # Consume some tokens and check ratio
reqTime += 1.seconds
let lastTimeFull_2 = reqTime
check bucket.tryConsume(400, reqTime) == true
check bucket.getAvailableCapacity(reqTime) == (600, 1000, lastTimeFull_2)
# Consume more tokens
reqTime += 1.seconds
check bucket.tryConsume(300, reqTime) == true
check bucket.getAvailableCapacity(reqTime) == (300, 1000, lastTimeFull_2)
# Test when period has elapsed (should return 1.0)
reqTime += 1.minutes
check bucket.getAvailableCapacity(reqTime) == (1000, 1000, lastTimeFull_2)
let lastTimeFull_3 = reqTime
# Test with empty bucket
check bucket.tryConsume(1000, reqTime) == true
check bucket.getAvailableCapacity(reqTime) == (0, 1000, lastTimeFull_3)
test "TokenBucket getAvailableCapacity compensating":
let now = Moment.now()
var reqTime = now
var bucket =
TokenBucket.new(1000, 1.minutes, ReplenishMode.Compensating, lastTimeFull = now)
let lastTimeFull_1 = reqTime
# Test full bucket capacity
check bucket.getAvailableCapacity(reqTime) == (1000, 1000, lastTimeFull_1)
# Consume some tokens and check available capacity
reqTime += 1.seconds
let lastTimeFull_2 = reqTime
check bucket.tryConsume(400, reqTime) == true
check bucket.getAvailableCapacity(reqTime) == (600, 1000, lastTimeFull_2)
# Consume more tokens
reqTime += 1.seconds
check bucket.tryConsume(300, reqTime) == true
check bucket.getAvailableCapacity(reqTime) == (300, 1000, lastTimeFull_2)
# Test compensation when period has elapsed - should get compensation for unused capacity
# We used 700 tokens out of 1000 in 2 periods, so average usage was 35% per period
# Compensation should be added for the unused 65% capacity (up to 25% max)
reqTime += 1.minutes
let (availableBudget, maxCap, _) = bucket.getAvailableCapacity(reqTime)
check maxCap == 1000
check availableBudget >= 1000 # Should have compensation
check availableBudget <= 1250 # But limited to 25% max compensation
# Test with minimal usage - less consumption means less compensation
bucket = TokenBucket.new(1000, 1.minutes, ReplenishMode.Compensating)
reqTime = Moment.now()
check bucket.tryConsume(50, reqTime) == true
# Use only 5% of capacity (950 remaining)
# Move to next period - compensation based on remaining budget
# UsageAverage = 950/1000/1.0 = 0.95, so compensation = (1.0-0.95)*1000 = 50
reqTime += 1.minutes
let (compensatedBudget, _, _) = bucket.getAvailableCapacity(reqTime)
check compensatedBudget == 1050 # 1000 + 50 compensation
# Test with full usage - maximum compensation due to zero remaining budget
bucket = TokenBucket.new(1000, 1.minutes, ReplenishMode.Compensating)
reqTime = Moment.now()
check bucket.tryConsume(1000, reqTime) == true # Use full capacity (0 remaining)
# Move to next period - maximum compensation since usage average is 0
# UsageAverage = 0/1000/1.0 = 0.0, so compensation = (1.0-0.0)*1000 = 1000, capped at 250
reqTime += 1.minutes
let (maxCompensationBudget, _, _) = bucket.getAvailableCapacity(reqTime)
check maxCompensationBudget == 1250 # 1000 + 250 max compensation
test "TokenBucket custom budget parameter":
let now = Moment.now()
# Test with default budget (-1, should use budgetCap)
var bucket1 = TokenBucket.new(1000, 1.seconds, budget = -1)
let (budget1, budgetCap1, _) = bucket1.getAvailableCapacity(now)
check budget1 == 1000
check budgetCap1 == 1000
# Test with custom budget less than capacity
var bucket2 = TokenBucket.new(1000, 1.seconds, budget = 500)
let (budget2, budgetCap2, _) = bucket2.getAvailableCapacity(now)
check budget2 == 500
check budgetCap2 == 1000
# Test with budget equal to capacity
var bucket3 = TokenBucket.new(1000, 1.seconds, budget = 1000)
let (budget3, budgetCap3, _) = bucket3.getAvailableCapacity(now)
check budget3 == 1000
check budgetCap3 == 1000
# Test with zero budget
var bucket4 = TokenBucket.new(1000, 1.seconds, budget = 0)
let (budget4, budgetCap4, _) = bucket4.getAvailableCapacity(now)
check budget4 == 0
check budgetCap4 == 1000
# Test consumption with custom budget
check bucket2.tryConsume(300, now) == true
let (budget2After, budgetCap2After, _) = bucket2.getAvailableCapacity(now)
check budget2After == 200
check budgetCap2After == 1000
check bucket2.tryConsume(300, now) == false # Should fail, only 200 remaining
test "TokenBucket custom lastTimeFull parameter":
let now = Moment.now()
let pastTime = now - 5.seconds
# Test with past lastTimeFull (bucket should be ready for refill)
var bucket1 = TokenBucket.new(1000, 1.seconds, budget = 0, lastTimeFull = pastTime)
# Since 5 seconds have passed and period is 1 second, bucket should refill
check bucket1.tryConsume(1000, now) == true
# Test with current time as lastTimeFull
var bucket2 = TokenBucket.new(1000, 1.seconds, budget = 500, lastTimeFull = now)
check bucket2.getAvailableCapacity(now) == (500, 1000, now)
# Test strict mode with past lastTimeFull
var bucket3 = TokenBucket.new(
1000, 1.seconds, ReplenishMode.Strict, budget = 0, lastTimeFull = pastTime
)
check bucket3.tryConsume(1000, now) == true # Should refill to full capacity
# Test compensating mode with past lastTimeFull and partial usage
var bucket4 = TokenBucket.new(
1000, 2.seconds, ReplenishMode.Compensating, budget = 300, lastTimeFull = pastTime
)
# 5 seconds passed, period is 2 seconds, so 2.5 periods elapsed
# Usage average = 300/1000/2.5 = 0.12 (12% usage)
# Compensation = (1.0 - 0.12) * 1000 = 880, capped at 250
let (availableBudget, _, _) = bucket4.getAvailableCapacity(now)
check availableBudget == 1250 # 1000 + 250 max compensation
test "TokenBucket parameter combinations":
let now = Moment.now()
let pastTime = now - 3.seconds
# Test strict mode with custom budget and past time
var strictBucket = TokenBucket.new(
budgetCap = 500,
fillDuration = 1.seconds,
mode = ReplenishMode.Strict,
budget = 100,
lastTimeFull = pastTime,
)
check strictBucket.getAvailableCapacity(now) == (500, 500, pastTime)
# Should show full capacity since period elapsed
# Test compensating mode with custom budget and past time
var compBucket = TokenBucket.new(
budgetCap = 1000,
fillDuration = 2.seconds,
mode = ReplenishMode.Compensating,
budget = 200,
lastTimeFull = pastTime,
)
# 3 seconds passed, period is 2 seconds, so 1.5 periods elapsed
# Usage average = 200/1000/1.5 = 0.133 (13.3% usage)
# Compensation = (1.0 - 0.133) * 1000 = 867, capped at 250
let (compensatedBudget, _, _) = compBucket.getAvailableCapacity(now)
check compensatedBudget == 1250 # 1000 + 250 max compensation
# Test edge case: zero budget with immediate consumption
var zeroBucket = TokenBucket.new(100, 1.seconds, budget = 0, lastTimeFull = now)
check zeroBucket.tryConsume(1, now) == false # Should fail immediately
check zeroBucket.tryConsume(1, now + 1.seconds) == true # Should succeed after period